The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 29, 2005
Filed:
Aug. 18, 2004
Shuh-haw Sheen, Naperville, IL (US);
Apostolos C. Raptis, Downers Grove, IL (US);
Hual-te Chien, Naperville, IL (US);
Shuh-Haw Sheen, Naperville, IL (US);
Apostolos C. Raptis, Downers Grove, IL (US);
Hual-Te Chien, Naperville, IL (US);
The University of Chicago, Chicago, IL (US);
Abstract
A sensor and detection methods are provided for detecting nitric oxides (NOx) in an exhaust gas based upon ion mobility spectrometry (IMS) technique. An ionization chamber having an interior electrically conductive shell receives exhaust gas. A spark electrode having a needle tip extends into the ionization chamber. A shutter grid is coupled between the ionization chamber and an ion drift tube. A substantially continuous spark discharge is established between the electrically conductive shell and the needle tip of the spark electrode for ionization of the exhaust gas. Negative NOions are kept inside the chamber by biasing the electrically conductive shell and the shutter grid at a negative voltage. Then a positive pulse is applied to the shutter grid to cause the shutter to open for negative NOions to exit into the ion drift tube. The IMS sensor is small-sized, low-cost, robust, and reliable.